5-phenyl-2-cyclopropylamino-4-oxazolinone, and process for making the same

ABSTRACT

New 5-aryl-2-cycloalkylamino-4-oxazolinones of the formula:   D R A W I N G

United States Patent [111 3,609,159

[ 1 Inventors Don Pierre Guidicelli 3,037,990 6/1962 l-lardy et a1, 260/307 Val de Marne; 3,047,461 7/1962 Hardy et a1. 260/307 Henry Naier, Paris, both of France [21] Appl. No. 655,002

[22] Filed July 21, 1967 [45] Patented Sept. 28, 1971 [73] Assignee Les Laboratoires Dausse Paris, France [32] Priority Mar. 1, 1963,Mar. 15, 1963, Sept. 24,

[33] France [311 926,545, 928,067 and 32,611

Continuation-impart of application Ser. No. 580,908, Sept. 21, 1966, now abandoned Continuation-impart of application Ser. No. 348,296, Feb. 28, 1964, now abandoned.

[54] 5-PHENYL-2-CYCLOPROPYLAMlNO-4- OXAZOLINONE, AND PROCESS FOR MAKING THE SAME 2 Claims, No Drawings [52] U.S. Cl 260/307 A,

260/544 M, 260/553 E, 424/272 [51] Int. Cl C07d 85/30 [50] Field of Search ..260/307 (1) [56] References Cited UNITED STATES PATENTS 2,892,753 6/1959 Schmidt et a1. 260/307 3,029,189 4/1962 Hardy et a1. 260/307 OTHER REFERENCES Najer et al., Bull. Soc. Chim. France, Ser. 5, pages 1810- 1813 (1963).

Primary Examiner-Alton D. Rollins Attorney-Stevens, Davis, Miller & Mosher ABSTRACT: New 5-aryl-2-cycloalkylamino-4-oxazolinones of the formula:

in the form of racemate or optical isomer and its acid addition salts, wherein R., R R R and R, are each hydrogen. halogen, trifluoromethyl, lower alkyl, lower alkoxy. amino. amino substituted by one or two alkyl. cycloalkyl or aryl radicals, or by an aliphatic, alicyclic or aromatic acyl radical. an aliphatic, alicyclic or aromatic acyl radical. alkylmercapto. sulphonamido, monoor di-substituted sulphonamido. cyano, or a substituted or unsubstituted carbamoyl radical; n is l. 2. 3 or 4; and R is hydrogen, lower alkyl. cycloalkyl. or lower w-hydroxyalkyl are useful as stimulants of the central nervous system and as anorexic agents.

-PHENYL-2-CYCLOPROPYLAMINO-4-OXAZOLINONE, AND PROCESS FOR MAKING THE SAME These compounds may be prepared by cyclizing a compound of the formula:

in which Hal denotes a halogen atom, more especially a chlorine atom, and R, R R2, R3, R and R5 are as aforesaid, the cyclization being effected by heating the said urea compound in the presence of the calculated amount of sodium alcoholate or other suitable hydrogen halide acceptor.

This application is a continuation-in-part of copending applications Ser. No. 348,296 filed Feb. 28, 1964, and Ser. No. 580,908, filed Sept. 21, 1966, and both now abandoned.

This invention relates to new compounds, their preparation and pharmaceutical compositions containing the same, more particularly to new oxazolinones which, as stimulants of the central nervous system and anorexic agents, are unexpectedly more potent than the 5-phenyl-2-unsubstituted and substituted amino-4-oxazolinones heretofor proposed for these purposes.

The present invention provides, as new compounds in both racemic and optically active forms, the oxazolinones of the formula and their acid addition salts, wherein R R R R, and R are each hydrogen, halogen (such as chlorine, bromine, iodine or fluorine), trifluoromethyl, lower alkyl, lower alkoxy, amino, amino substituted by one or two alkyl, cycloalkyl, or aryl radicals, or by an aliphatic, alicyclic or aromatic acyl radical, an aliphatic, alicyclic or aromatic acyl radical, alkylmercapto, sulfonamido, monoor disubstituted sulfonamido, cyano, or a substituted or unsubstituted carbamoyl radical; n is l, 2, 3 or b 4; and R is hydrogen, lower alkyl, cycloalkyl, or lower tohydroxy-alkyl.

Especially valuable compounds of formula 1 are those in which R, R R R and R are each hydrogen, halogen or lower alkyl, R is hydrogen or lower alkyl, and n is l, 2, 3, or 4.

The new oxazolinones may be prepared by cyclizing a urea compound of the formula:

R Rr I -Qa r 01 NH R4 R5 RN-CH CH II The starting material of formula 11 may be prepared by condensing an a-aryl-a-chloracetyl chloride of formula III with a urea of formula IV, the symbols being as defined above, in accordance with the following reaction scheme:

1 I f 2)n l C1 C1 CH2 R4 5 III IV conventional manner, bearing in mind that those compounds in which n=l are somewhat sensitive to acid, and that it is necessary in such cases to insure that the cyclopropyl ring is not destroyed by the action of the acid. This may be done, for example, by preparing the salt in an inert anhydrous medium, such as diethyl ether or benzene. The base and the appropriate acid are mixed together in stoichiometric proportions, and the acid addition salt isolated in the usual manner.

The invention will be further understood by the following description in which are included examples of the process for the production of these novel compounds and of the preparation and use of pharmaceutical compositions therefrom. It will be understood that the several examples are intended to be illustrative of the invention and not in any way a limitation thereof.

It is well known that 5-phenyl-2-amino-4-oxazolinone is a stimulant for the central nervous system, and that a few Nsubstituted derivatives thereof are more powerful stimulants than said 5-phenyl-2-amino-4-oxazolinone, to wit in the order of decreasing activities, the 2monoethylamino, 2- monomethylamino and 2-dimethylamino derivatives. It is further known that in the 2-monoalkylamino derivative series, the activity decreases very quickly from 2 carbon atoms in the alkyl group upwards and eventually is reversed. More particularly the n-monopropylamino derivative shows but a very low activity and the monoisopropylamino compound shows no activity.

It was thus quite unexpected to find that although having a 3-carb0n atom group attached to the nitrogen atom in the 2- position, a 5-phenyl-2-mono-substituted amino-4-oxazolinone is definitely more potent than all above named, stimulating compounds.

EXAMPLE I a. N -cyclopropyl-N'-(alpha-phenyl-alpha-chloro-acetyl) urea:

Into a three-necked spherical flask having a capacity of 1 liter and provided with a dropping funnel, a condenser surmounted by a calcium chloride tube and a mechanical stirrer, there were suspended 17.6 g. (0.176 g.-mol) of cyclopropylurea and 21.3 g. (0.176 g.-mol) of dimethylaniline in 310 ml. of anhydrous benzene. While stirring, there was added through the dropping funnel in 45 minutes a solution of 33.3 g. (0.176 g.-mol) of alpha-phenyl-alpha-chloroacetyl chloride in 130 ml. of anhydrous benzene. The mixture was then left at ambient temperature with stirring for 1 hour then heated under reflux on the water bath with stirring for 5 hours.

The benzene solution was decanted while still warm and thereby separated from an oil deposited on the flask wall, the benzene was evaporated on the water bath in vacuo, the oily residue was triturated 3 successive times in ml. of ether, ether being decanted each time, the last traces of ether were removed in vacuo, then the oil was triturated in 250 ml. of water until it crystallized. The crystalline precipitate was filtered off, copiously washed with water and dried in vacuo over phosphorus pentoxide.

There were thus recovered 24.7 g. (yield 55 percent) of N cyclopropyl- N (alpha phenyl alpha chloroacetyl) urea which, when recrystallized from 400 ml. of a mixture of ethyl TABLE 1 alcohol and hexane (1 4), had a melting point of 134l 35 5 'f 8 Dumb" C oxazohnone gJkg. intensity of duration compound (i.p.) of motive maximum of Analysis C H ClN 02 (M01 weight 252.5) "citation activity admin percent calc. C 57.03 H 5.15 Cl 14.05 N 11.09 (minutes) (hours) percentfound 56.88 5.09 13.33 11.16

10 Z-monocycltr from +H- 120-180 6 b. 5-phenyl-2-monocyclopropylamino-4-oxazolinone. propylamino 0.01 w 16.6 g. (0.066 g.-mol.) of this N -cyclopropyl-N"- alphaizrjf 6 phenyl-alpha-chloroacetyl)-urea was dissolved in a sodium zqnonwhyb 3M0 how 3 ethoxide solution containing 1.5 g. (0.066 g.-atom) of sodium amino 0.01 to in 330 ml. of absolute ethyl alcohol, and the mixture was y 120-180 0 heated under reflux for 2 hours. The precipitated sodium f chloride was filtered ofi, alcohol was evaporated from the fil- 3:21 0 05 I? I; trate on the water bath in vacuo, the gummy residue was tritu- Comm rated in 150 ml. of water until it crystallized, and the compound was filtered off, copiously washed with water and dried in vacuo over phosphorus pentoxide.

There were recovered 11.4 g. (yield 80 percent) of S-pheniz ffiizw t h i "T grates! mom: yl-2-monocyclopropylamino-4-oxazolinone which, when a m es e F recrystallized from 500 ml. of a mixture of ethyl alcohol and e same expenmem l out by admlmstenng hexane (1 :4), had a melting point of l39-140 C. p unds orally gave very similar results except as regards the UV spectrum (in ethanol): Amax; 224 MMFZSQOO) monomethylamino compound, which was inferior to the IR spectrum (in KBr): 1740 cm. c=0), 1640 cm. c mofloethylamim compound- N) The central nervous system stimulating properties of this Anal Sis C H N 0 Mo] Wei ht 216 new monocyclopropylamino 4-oxazolinone were further y 12 2 2( g demonstrated by the inhibiting effect that said compound produces towards the depressing effects of reserpine. 2:3,; C 2F H 51 N Two lots of 10 mice were given orally 0.010 gJkg. of the 66.74 5.60 -oxazolinone new compound (first lot) and 0.010 gJkg. of til-amphetamine 5.phenyl-2.monocyclop oyl3mifl0-4-() azolinone is a white (second [0!) a hil'd lot Of mic served as a control. 2 crystalline substance which is soluble in cold ethyl alcohol, inhours after the ing i n of the above substances by the soluble in water, stable in alkaline medium but unstable in anim s n th rs! t 1018, the mice in the three lots were acid medium. A suspension of the oxazolinone in boiling 1O given 0.002 gJkg. of reserpine (dissolved in a mixture of percent aqueous solution of sulfuric acid, is converted very acetic acid, propylene-glycol and water) by the inquickly to S-phenyl-oxazolidine-Z, 4-dione. 40 traperitoneal route. The animals were then observed 1 hour, 3 The corresponding Z-monoeyclobutylamino, 2-mon0- hours and 18 hours after the injection of reserpine. The results cyclopentylammo and 2-monocyclohexylamino compounds are tabulated below:

TABLE II Dosage Spontaneous activity after injecting reserpine 5- h 14-0 azolinone compound ag 0 1 hour 3 hours 18 n31";

p eny X 2-monocyclopropylamino 0.010 ptosis 8/10 ptosis 7/10. dl-Amphetamine 0. 010 ptosis 10/10 ptosis 10/10. Controls ptosis 10/10 ptosis 10/10.-- ptosis 10/10.

1 1 d 1311. 2 2 d tlis.

N oTE.i-++ strong depression; mean depression; weak depression; definite activity.

may be prepared similarly. However, when tested, these compounds exhibit no pharmacological activity whereas the 2- monocyclopropylamino compound exhibits central nervous system stimulating properties and anorexigenic properties much more potent than those of 5-phenyl-2(unsubstituted) amino-4-oxazolinone, of the various S-phenyl-Z-monoloweralkylamino-4-oxazolinones, and of 5-monocyclopropylamino-4-oxazolinone has much more favorable therapeutic index and margin of safety than the other S-phenyl-2-amino-4-oxazolinones (whether substituted or not in the amino group in the 2-position).

Observations made after injecting intraperitoneally in mice 0.01 g.lkg. of 5-phenyl-2-monocyclopropylamino-4-oxazolinone comparatively with the following known com pounds administered by the same route: 5-phenyl-2- monomethylamino-4-oxazolinone (0.05 g.lkg.), 5-phenyl-2- monoethylamino-4-oxazolinone (0.01 g./kg. and 0.05 gJkg.) and 5-phenyl-2-dimethylamino-4-oxazolinone (0.05 g./kg.), are set out in the following table:

The above table shows that S-phenyl-Z-mono cyclopropylamino-4-oxazolinone produces antidepressing effects at least equal to those caused by til-amphetamine towards the action of reserpine.

EXAMPLE ll The reaction mixture is then left for 1 hour at ambient temperature. The reaction is finished by heating under reflux for 5 hours on a water bath. The mixture is allowed to cool. An oil which has deposited on the walls of the flask is separated, the benzene is evaporated on a water bath in vacuo, the oily residue is triturated successively three times with 100 ml. of ether with decantation on each occasion, the last traces of ether are removed in vacuo, and the oil is then triturated with 250 ml. of water until it crystallizes. The crystals are filtered ofi, copiously washed with water, and the compound dried in vacuo over phosphorus pentoxide. 28.6 g. (56 percent yield) of N-cyclopropyl-N'-(a-p-chlorophenyl-a-chloroacetyl)urea are obtained. After recrystallization from isopropyl alcohol, it melts at 132 C.

Analysis for CmHuClgNgOz (M.W.

Calc. percent: C==50.18 percent l-l=4.l8 percent Cl=24.74 percent N=9.76 percent Found: @5027 percent l-l=4.07 percent C1=24.51 percent N=9.81 percent b. 5-(p-chlorophenyl)-2-cyclopropylamino-4-oxazolinone 28.7 g. (0.1 g. mole) of N-cyclopropyl-N-(a-p-chlorophenyla-chloroacetyl urea dissolved in a solution of sodium ethoxide obtained by dissolving 2.3 g. (0.1 g. atom) of sodium in 500 ml. of absolute alcohol, and the mixture is heated for 2 hours under reflux. The sodium chloride produced is filtered off, the alcohol is evaporated from the filtrate on a water bath in vacuo, the gummy residue is triturated with 250 ml. of water until it crystallizes, and the compound is filtered off, copiously washed with water and dried in vacuo over phosphorus pentoxide. 18.5 g. (64.5 percent yield) of 5-p-chlorophenyl-2- cyclopropylamino-4-oxazolinone are obtained. After recrystallization from absolute alcohol, it melts at 21 1 C.

Analysis for cflflnclNzog (M.W.=250.5)

Calc. C=57.49 percent 1-l=4.38 percent Cl=l4.l7 percent N=1 1.16 percent Found: C=57.41 percent 1-l=4.32 percent Cl=14.3 1 percent N=11.29 percent EXAMPLE lIl Preparation of 5-pheny1-2-(N-cyclopropyl-N-methylamino)-4 -oxazolinone a. ltI-cyclopropyl-N-methy1-N'-(oz-phenyl-oz-chloractyl)- urea 11.4 g. (0.1 g. mole) of N-cyclopropyl-N-methyl urea, 12.1 g. (0.1 g. mole) of dimethylaniline and 200 ml. of anhydrous benzene are introduced into a 1 liter. three-necked,

round-bottom flask provided with a dropping funnel, a mechanical stirrer, and a reflux condenser closed with a calcium chloride tube. 18.9 g. (0.1 g. mole) of a-phenyl-achloracetyl chloride in 100 ml. of anhydrous benzene are added to this suspension, which is stirred mechanically. from the dropping funnel over the course of 1 hour. The reaction mixture is left for 1 hour at room temperature, and the reaction is then completed by heating under reflux for several hours on a water bath. The mixture is allowed to cool, the supernatant liquid is decanted from the oil sticking to the walls of the flask, and the oil is then triturated three times with 100 ml. of diethyl ether each time. After removal of the last traces of ether in vacuo, the oil is triturated with 150 ml. of water until it crystallizes. The crystalline residue is then filtered off, washed with water and dried in vacuo over phosphorus pen toxide. 13.2 g. (50 percent yield) of N-cyc1opropyl-N'-methyl- N'-(a-phenylchloracetyl) urea are obtained.

Analysis for c,,H,,N,0,c1 (M.W =266.5)

Calc: C=58.54 percent l-l=5 .63 percent N=l0.50 percent Found: C=58. l 3 percent l-l=5.6l percent N=l0.4l percent 58.42 percent 5.82 percent 10.68 percent b. 5-phenyl-2-(N-cyclopropyl-N-methylarnino)-4-oxalinone 26.6 g. (0.1 g. mole) of N-cyclopropyl-N-methyl-N'-(a-pheny1-a-chloracetyl)urea are dissolved in a solution of sodium ethoxide obtained by dissolving 2.3 g. (0.1 g. atom 1 of sodium in 500 ml. of absolute ethanol, and the mixture is heated for 2 hours under reflux. The sodium chloride produced is filtered off, the alcohol is evaporated from the filtrate on a water bath in vacuo, and the gummy residue is triturated with 250 ml. of water until it crystallizes. The crystalline residue is filtered off, washed with water and dried in vacuo over phosphorus pentoxide. 15.1 g. (60 percent yield) of S-phenyl-Z-(N- cyclopropyl-N-metl'iylamino)-methylamlno)-4-oxazolinone are obtained. After recrystallization from a mixture of ethyl acetate and hexane (2:3), it melts at C. Analysis for C, H N O, (M.W.=230) Calc. C=67.83 percent l-l =6.09 percent N=l2.l7 percent Found: C=67 .80 percent l-l=6.13 percent N=1 1.95 percent 67.61 percent 6.28 percent 12.20 percent The ultraviolet absorption spectrum shows Amax. C,H,OH= 230 1,. e=28,000v

k increase in motor activity with reference 10 the controls 30 minutes alter 60 minutes after Dose (mg/kg.) administration administration In equal doses, d-amphetamine provokes essentially the same motor hyperactivity but is less long-lasting in effect. In addition, amphetamine is a convulsent, unlike the new compounds.

Tests carried out in rats according to the method of A. P. Roszkowski et al. (J. Pharmacol. Exp. Th. 1963, 140, 367) show that the ED 50 of the Z-monocyclopropylamino compound of example 1 and d-amphetamine are very similar, to WIL' d-amphetamine 2.6 mgJkg.

2-monocyc1opropy1amine compound 3.1 mgJkg.

The anorexigenic effect of the compound of example 111 likewise is not significantly different from that of damphetamine. The oral toxicity of this new compound administered orally in the mouse is less than that of damphetamine. This compound has only a very slight cardiovascular effect in the cat or dog in doses up to 5 mgjkg. ad ministered parenterally.

The toxicity of the 5-phenyl-2-monocyclopropylaminc-4- oxazolinone is low in comparison with the activity thereof. Thus, while said activity was found to be four to five times greater than that of 5-phenyl-2-monoethylamino-4-oxazolinone (the most potent compound per os in the group of Z-monoalkylamino and Z-dimethylamino compounds), the respective lethal doses (LD 50) are S-phenyl-Z-monovth ylamino-4-0xaz0liu0ne. G./kg. Intraporitonoal routt- 0. Subcutaneous rouu- U. 340

5-phenyl-2-monocyclo iro 1vlamino-4-oxaz0liu0ue Intraperitoueal route 0. 081 Subcutaneous route. 0. 142

Thus while the Z-cyclopropylamino compound is four to five times more active than the Z-monoethylamino compound, the toxicity of the first one is only 2.5 times greater than that of the second one, ie has a therapeutic index about twice better.

These new -phenyl-2-cyclopropylamino-4-oxazolinones may be employed for therapeutic purposes:

I. As a psychotonic drug:

in depressive states having various causes, to combat physical and mental asthenia and to increase the psychic tonus and the power of concentration and attention:

in states in which anxiety with inhibition constitutes a dominant symptom, to produce the reappearance of spirit" with the resumption of rational activity and the power to analyze facts logically.

ll. As an antifatigue" agent by means of which it is possible to postpone the hour of normal sleep without inhibiting sleep on retiring to bed.

[11. As an anorexigenic.

The invention includes within its scope pharmaceutical compositions comprising a compound of formula I in associa tion with a compatible pharmaceutically acceptable diluent or carrier, and preferably in a form suitable for oral administration. Each unit dose should contain an amount of active ingredient such that a daily dose of l to l,000 mg. of active substance can be spread over two to four unit doses. For the compound of example Ill, a daily dose of l to 50 mg. in unit doses each containing 1 to mg. is generally suitable. The compound of example I may be administered orally in the form of tablets containing from 1 to 30 mg. of active substance; a daily dosage of from 1 to about mg. being preferred where the production of anorexic effects is to be sought, while higher dosages, eg about 15 to about 60 mg, are preferably adopted where stimulation of the central nervous system is particularly sought.

An example of a composition for a tablet is as follows:

5-phenyl-2-cyclopropylaminod-oxazolinone 0.001 g. Lactose 0.0635 g. Corn starch 0.008 g. Tricalcium phosphate 0.025 g, Orange yellow S 0.0005 g. Magnesium stearate 0.002 g.

Particularly advantageous forms of oral administration of the new compounds are provided by S-phenyl-Z- cyclopropylamino-4-oxazolinone fixed on certain pharmaceutically acceptable synthetic resins of the cation exchange resin type, for example cation exchange resins containing sulfonic groups, a suitable one being Amberlite IR. 120 {H} Such a resin with the 5-phenyl-2-cyclopropylamino- 4-oxazolinone fixed thereon may be depicted as an acid addition salt which may be termed a resinate."

An advantage of such a resinate" is that the new amine is gradually liberated therefrom in the organism after it has been administered. Hence the therapeutic action is protracted and the total daily dosage of drug may be administered at one go, a point believed particularly important as the new compound is anorexigenic to a considerable degree.

with a view to preparing such a resignate," a solution of S- phenyl-2-cyclopropylamino-4-oxazolinone may be passed through a column or bed of the cation exchange resin until the 5-phenyl-2-cyclopropylamino-t-oxazolinone content in the effluent is the same as in the feed; the proportion of oxazolinone compound thus fixed varies according to the cation exchange resin.

The resinates" are preferably encapsuled, e.g. in conventional gelatin capsules containing l to 60 mg. of 5-phenyl-2- cyclopropylamino-t-oxazolinone. For example, one capsule may contain 5 mg. of said oxazdinone fixed on the required amount of Amberlite LR. [l-l} for saturation with said oxazolinone.

It should be understood, of course, that the foregoing disclosure relates only to preferred embodiments of the invention and that it is intended to cover all changes and modifications of the examples of the invention herein chosen for the purposes of the disclosure which do not constitute departures from the spirit and scope of the invention.

We claim:

1. A compound of the formula and the nontoxic acid addition salts thereof. 2. A method for producing the compound of the formula C CH;

which comprises heating to reflux temperature in a lower aliphatic alcohol medium a mixture of sodium ethoxide with an equimolecular amount of a urea of the formula wherein hal is halogen, to cyclize said urea. 

